U.S. Pat. Nos. 4,672,929 and 4,773,362 disclose an internal combustion engine having an automatic starting arrangement which includes a pneumatic positioning member engaging the starter flap (choke flap) of the engine. The positioning member is connected via a check valve to the crankcase of the engine which is started manually. When the engine starts running, then the changing crankcase pressure is applied to the check valve so that only the negative pressure components are allowed to pass. The positioning member includes a bellows which is evacuated so that the positioning rod associated with the bellows pivots the starter flap into its no-choke at-rest position in which the intake channel is clear and the engine runs.
When the engine is switched off, then the under pressure in the bellows drops since the bellows is ventilated via a compensating line. The positioning rod returns and pivots the starter flap into its start position for the next starting attempt.
Such an internal combustion engine has an electrical ignition system which is a flywheel ignition or magneto ignition in motor-driven tools such as lawn mowers, motor-driven chain saws or the like. To bring the engine to standstill, the ignition coil is connected to ground while the engine is running so that the spark plug can no longer provide sparks because of the short circuit which has occurred and the engine coasts to standstill. This short circuiting of the ignition coil occurs mostly via an ignition switch which short circuits the ignition coil in its first position (the engine coasting to standstill) and which, in a second switching position, interrupts the short circuit (the engine runs).
In practice, it has been shown that the switch is brought into the correct switch position for switching off the internal combustion engine; however, the return switching into the start position (ignition-enabling position) often does not occur when starting the engine. For a start-up operation wherein the ignition is switched so that it is disabled, the start-up operation leads to an over enrichment of the mixture in the combustion chamber of the engine and this, in turn, leads to considerable difficulties in subsequent starting attempts with the ignition switched so that it is enabled. This is problematical especially with manually started internal combustion engines.